1. Field of the Invention
This invention relates to the manufacture of cooled and cleaned gaseous mixtures comprising H.sub.2 and CO, and by-product superheated steam. More particularly it pertains to a process for the manufacture of a cooled and cleaned stream of synthesis gas, fuel gas, or reducing gas, and by-product superheated steam by the partial oxidation of ash containing solid carbonaceous fuels.
2. Description of the Prior Art
The hot raw gas stream leaving a gas generator in which an ash containing solid fuel is burned will contain various amounts of molten slag and/or solid material such as soot and ash. It will often be necessary, depending on the intended use for the gas, to reduce the concentration of these entrained solid materials. By removing solids from the gas stream, one may increase the life of apparatus located downstream that is contacted by the raw gas stream. For example, the life of such equipment as gas coolers, compressors, and turbines, may be increased.
In co-assigned U.S. Pat. No. 2,871,114-Du Bois Eastman, the hot raw gas stream leaving the gas generator is directed into a slag pot and then into a quench accumulator vessel where all of the ash is intimately contacted with water. All of the sensible heat in the gas stream is thereby dissipated in the quench water at a comparatively low temperature level; and the gas stream leaving the quench tank is saturated with H.sub.2 O. U.S. Pat. No. 3,988,123 provides for a vertical 3-stage gasifier including a combustion stage, an intermediate cooling stage, and a heat recovery stage. In such a scheme not only is a portion of the sensible heat in the hot gases leaving the combustion stage lost in the cooling stage but small particles of solidified ash tend to plug the tubes in the boiler located under the gas generator. Other waste heat boilers have been proposed for use in recovering heat from gases, for example, the apparatus described in U.S. Pat. No. 2,967,515 in which helically coiled tubes are employed. Waste-heat boilers containing a combination of straight and helical, spiral, and surpentine coiled heat exchange tubes are also used. Boilers of such general design are high in cost. Further, the sharp bends in such coils make the tubes vulnerable to plugging, difficult to remove and replace, and expensive to clean and maintain.